Statistics & Math Interview Questions
Practice 482 real Statistics & Math interview questions for 2026 — Statistics & Math interview questions gathered from actual interviews, with detailed solutions to guide your interview preparation. Covers companies like Meta, Capital One, Google, Amazon, and Optiver and roles such as Data Scientist, Quant/Trader, ML researcher, and Data Analyst. This collection is distinctive because problems range from applied inference
"I got asked a hardcore MCM DP question and I saw it on PracHub as well. Solved that question in 5 minutes. Without PracHub I doubt I could solve it in 5 hours. Though somehow didn't get hired, perhaps I guess I solved it too fast? /s"
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"Discovered PracHub 10 days before my interview. By day 5, I stopped being nervous. By interview day, I was actually excited to show what I knew."
"I recently cleared Uber interviews (strong hire in the design round) and all the questions were present in prachub."
"The search is what sold me. I typed in a really niche DP problem I got asked last year and it actually came up, full breakdown and everything. These guys are clearly updating it constantly."
Decide if subgroup increases imply overall increase
TikTok Time: Subgroup Increases vs Overall Average (Simpson's Paradox) You are analyzing average daily time spent on TikTok by gender (male, female) a...
Define and compute retention and churn precisely
Retention and Churn for a Transactional Consumer App Context: You are analyzing retention and churn for a transactional consumer app (e.g., food deliv...
Compute sample size and plan experiment
A/B Test Planning: Paywall Copy Change For New Signups Context You are planning an A/B test to evaluate a paywall copy change that targets new signups...
Compute posterior for accurate-but-rare classifier
Bayes' Theorem: Interpreting Screening Model Predictions Context You are evaluating a binary screening model that flags "bad" users in a population. T...
Analyze results and large p-values correctly
Experiment Analysis Plan: User-Level ITT with Robust Inference, Variance Reduction, Ratios, Skew, Non-Compliance, and Decision Framework Context You r...
Derive no-click probability and sketch implications
Click Probability Across Repeated Impressions Context: We show A impressions of the same item to a user. Unless otherwise stated, each impression is a...
Match Year-2 profit to Year-1
Target Profit Volume Across Two Years Context You sell only classic burgers. Year 1 has negligible fixed costs; Year 2 introduces new fixed costs. The...
Decide launch with p=0.10 at alpha 0.05
A/B Test Decision: Frequentist, Conditional Power, Bayesian, and Risk-Mitigation Context You ran a 50/50 A/B test on 30‑day subscriber retention. The ...
Differentiate LDA and QDA; compute boundary
Binary Gaussian Classification: LDA vs QDA You are modeling a 2D binary Gaussian classifier with features (x, y): - Class 0: mean μ0 = (0, 0), covaria...
Choose tests for rare-event A/B analysis
A/B Test for Rare Weekly Cancellations — Planning, Testing, and Monitoring You are testing whether a product change affects weekly cancellation probab...
Determine distribution of aX+b when X~N(0,1)
Linear Transform of a Standard Normal Setup - Let X ~ N(0, 1) (standard normal). - For constants a, b ∈ ℝ, define Y = aX + b. Tasks (a) What is the ex...
Generate Samples from Truncated Normal Distribution
Scenario You draw from a normal distribution but only keep observations that are greater than 1 (i.e., values below 1 are discarded). Assume the origi...
Analyze User Transfer Distribution in Initial Launch Period
P2P Payments: Transfers per User in the First 30 Days Scenario A new peer‑to‑peer (P2P) payments feature has just launched. You are asked to analyze h...
Derive Coefficient and Covariance in Regression Analysis
Correlation Structure, Regression Slopes, Covariance of Order Statistics, and Change-of-Variables You are given standard random variables and asked to...
Test Billboard Campaign Conversion Rate Exceeds 60%
One-Proportion Test for a Conversion Rate Context You ran a billboard campaign and measured conversions on a sample of N = 100 users. The observed con...
Test whether two distributions differ
You have two datasets collected from different systems or populations, and you want to determine whether they come from the same distribution. Explain...
Derive a CDF from a PDF
During a first-round Data Scientist interview, you are asked a coding-and-statistics question: You are given a valid probability density function f(x)...
Compute probability of drawing reds
Probability of Drawing at Least Two Red Balls Problem A bag contains 6 red balls and 4 blue balls. Three balls are drawn uniformly at random without r...
Determine Probability of Friend Request Being Fake
Scenario You operate a platform where 95% of accounts are real and 5% are fake. Fake accounts send 10 times as many friend requests per account as rea...
Calculate Expected Comments and Confidence Interval Analysis
Scenario You are analyzing the distribution of comment counts per post for a social platform feature over a fixed time window. Let X be the random var...